Super Wake on Final
At a Gulf hub, approach control is sequencing arrivals on ILS runway 30L in calm wind. An A380 crosses the threshold. An A320 is 6 NM in trail at 1,200 ft and has already been cleared to land; a second A320 is 12 NM behind. The A320 crew reports 'slight buffet' passing 900 ft. RVR is 1,200 m and the ceiling is 500 ft. The airport has no dedicated wake-turbulence radar, and the ATIS advertises runway 30L with wind 300/08. The tower coordinator asks whether the landing clearance can stand and how to sequence the remaining traffic.
1. What wake-turbulence separation minimum applies between the A380 and the A320, and was the landing clearance valid? State the action you would take.
Read the worked answer
The A380 is in the Super wake category and the A320 is Medium. ICAO wake-turbulence separation for a Super followed by a Medium on approach is 7 NM. At 6 NM in trail, the spacing is below the minimum, so the A320's landing clearance should not have been issued on that basis and cannot stand. The correct action is to cancel the landing clearance and instruct a go-around, then re-sequence the A320 at no less than 7 NM behind the Super. The fact that the A380 has crossed the threshold does not remove the wake; the turbulence persists behind the flight path. RVR and ceiling are not the limiting factor here.
2. The A320 reports buffet. What immediate phraseology and follow-up actions do you use?
Read the worked answer
Treat the report as evidence of wake encounter. Issue an immediate go-around: 'A320, go around, I say again, go around, wake turbulence.' Pass the missed-approach instructions and current wind, and ask for the crew's intentions. Do not issue a second approach clearance until the aircraft is established on the missed approach and spacing behind the Super can be rebuilt to at least 7 NM. Pass wake-turbulence information to the following A320 and consider delaying its descent or using speed control. Record the occurrence and notify the supervisor; the pilot report should be retained for the safety report.
3. How would you sequence the second A320, and what would you do if the crew requests a visual approach to keep the traffic moving?
Read the worked answer
The second A320 is 12 NM behind, which is acceptable only if it remains at least 7 NM behind the Super at the threshold. Speed control or a short vector can absorb excess spacing, but the minimum must not be reduced to 5 NM just because both aircraft are Medium. A visual approach does not waive wake-turbulence separation; the Super-to-Medium 7 NM minimum still applies. If the crew cannot accept the spacing, hold the aircraft or vector it for a new approach rather than compressing the sequence.